This is a C language opengles2.0 simple example how can I porting it to the sailfish platform

answered 2014-03-20 14:48:33 +0300

lbt
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http://www.merproject.org...

updated 2014-03-20 14:49:42 +0300

I'm assuming you're interested in the GLES aspect, not C or Wayland. Jolla's native apps are mainly Qt/C++ so I'll assume that's what you'll end up with.

Here's some code I use. I expect there's a lot wrong with it but it works for me :)

One day I plan to create a minimal setup for using GLES for the main graphics and QML for the chrome.

See http://qt-project.org/doc/qt-5.1/qtopengl/cube.html too

You need to create your own Myitem class which extends the GLItem

in main.cpp

int main(int argc, char *argv[])
{
    QScopedPointer<QGuiApplication> app(SailfishApp::application(argc, argv));
    QScopedPointer<QQuickView> view(SailfishApp::createView());

    qmlRegisterType<Myitem>("harbour.app.", 1, 0, "Myitem");
    view->setSource(SailfishApp::pathTo("qml/harbour-myitem.qml"));
    view->show();

    return app->exec();
}

in glitem.h

#ifndef GLITEM_H
#define GLITEM_H

#include <QtQuick/QQuickItem>
#include <QOpenGLFunctions>
#include <QtGui/QOpenGLShaderProgram>

class GLItem : public QQuickItem, protected QOpenGLFunctions
{
    Q_OBJECT

public:
    GLItem();
protected:
    virtual void prep() = 0;
    virtual void render() = 0;
public slots:
    void paint();
    void cleanup();
    void sync();
private slots:
    void handleWindowChanged(QQuickWindow *win);
protected:
    QOpenGLShaderProgram *m_program;

};
#endif // GLITEM_H

in glitem.cpp

#include <QtQuick/qquickwindow.h>
#include <QtGui/QOpenGLShaderProgram>
#include <QtGui/QOpenGLContext>
#include <QFile>
#include <QSurfaceFormat>

#include <QDebug>

GLItem::GLItem()
    : m_program(0)
{
    connect(this, SIGNAL(windowChanged(QQuickWindow*)), this, SLOT(handleWindowChanged(QQuickWindow*)));
}


void GLItem::handleWindowChanged(QQuickWindow *win)
{
    if (win) {
        // Connect the beforeRendering signal to our paint function.
        // Since this call is executed on the rendering thread it must be
        // a Qt::DirectConnection
        bool before = true;

        if (before)
            connect(win, SIGNAL(beforeRendering()), this, SLOT(paint()), Qt::DirectConnection);
        else
            connect(win, SIGNAL(afterRendering()), this, SLOT(paint()), Qt::DirectConnection);

        connect(win, SIGNAL(beforeSynchronizing()), this, SLOT(sync()), Qt::DirectConnection);

        // If we allow QML to do the clearing, they would clear what we paint
        // and nothing would show.
        if (before)
            win->setClearBeforeRendering(false);
        else
            win->setClearBeforeRendering(true);
    }
}

void GLItem::paint()
{
    if (!m_program) {
        m_program = new QOpenGLShaderProgram();
        connect(window()->openglContext(), SIGNAL(aboutToBeDestroyed()),
                this, SLOT(cleanup()), Qt::DirectConnection);
        initializeOpenGLFunctions();
        this->prep(); // Called once - setup here (eg create VBOs, shaders, load textures etc)
    }
    QRectF vpr = mapRectToScene(QRectF(0.0,0.0,width(),height()));
    glViewport( vpr.x(), (window()->height() -( vpr.y() + vpr.height())),
                vpr.width(), vpr.height());

    // save (not sure this is needed)
    float depthrange[2];
    glGetFloatv(GL_DEPTH_RANGE, depthrange);
    glDepthRangef(0.0, 1.0);

    float depthclear;
    glGetFloatv(GL_DEPTH_CLEAR_VALUE, &depthclear);
    glClearDepthf(1.0);

    glClearColor(0, 0, 0, 0);
    glDepthMask(true);

    glEnable(GL_DEPTH_TEST);
    glEnable(GL_CULL_FACE);

    // actually clear all depth information
    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);

    // Bind the program and render
    if (m_program->isLinked())
        m_program->bind();

    this->render(); // called every screendraw - do your rendering here
    // restore
    glDepthRangef(depthrange[0], depthrange[1]);
    glClearDepthf(depthclear);
}

void GLItem::cleanup()
{
    if (m_program) {
        delete m_program;
        m_program = 0;
    }
}
void GLItem::sync(){
}

in the qml:

Myitem {                                 id: myitem
    anchors.fill: parent
    MouseArea {                         id: bgMA
        anchors.fill: parent
        preventStealing: true
        Connections { // eg if you add touch handlers to your c++ code
            onPositionChanged: myitem.handlePositionChanged(mouse.x,mouse.y)
            onPressed: myitem.handlePressed(mouse.x,mouse.y)
            onReleased: myitem.handleReleased(mouse.x,mouse.y)
        }
    }
}